Add Java support to checkdeps.py

tools/checkdeps/checker.py

+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+
+
+class Checker(object):

[M-A Ruel, 2012/07/17 14:23:20]

Note that an "interface" is not a contractual definition in python. As such, I'm
not even sure this is useful.

Some people used Zope to simulate proper interfaces but this is just barely
useful. The only time I really use base classes is when a partial implementation
is needed.

In that case, there's _base_directory so it may be worth keeping it. In any
case, kill the Factory class.

[Iain Merrick, 2012/07/17 15:55:08]

OK, if you prefer to keep the contract implicit, this whole module can probably
go.

+  """Base class for language-specific checker modules.
+
+  Properties:
+    _base_directory: root directory against which imports are resolved.
+    _verbose: True if CheckFile should print detailed progress information.
+  """
+
+  def __init__(self, base_directory, verbose):
+    self._base_directory = base_directory
+    self._verbose = verbose
+
+  def Extensions(self):
+    """Returns a list of file extensions that this checker can handle."""
+    raise NotImplementedError(self.__class__.__name__ + ".Extensions")
+
+  def CheckFile(self, rules, file_name):
+    """Checks the given file with the given rule set.
+
+    Args:
+      rules: The set of rules that apply to files in this directory.
+      file_name: The source file to check.
+
+    Returns: Either a string describing the error if there was one, or None if
+             the file checked out OK.
+    """
+    raise NotImplementedError(self.__class__.__name__ + ".CheckFile")
+
+
+class Factory(object):

[M-A Ruel, 2012/07/17 14:23:20]

This is overdesign at that point; this is no Java. :D Remove this whole class.

+  """Helper class for locating the correct Checker for each file."""
+
+  def __init__(self, base_directory, verbose):
+    """Loads and initializes all known subclasses of Checker.
+
+    Args:
+      base_directory: root directory against which imports are resolved.
+      verbose: True if CheckFile should print detailed progress information.
+    """
+    self._checkers = [
+        c(base_directory, verbose) for c in Checker.__subclasses__()]
+
+  def GetChecker(self, filename):
+    """Returns the Checker for the given file, or None if no check is needed."""
+    basename, extension = os.path.splitext(filename)
+    for c in self._checkers:
+      if extension in c.Extensions():
+        return c
+    return None
+